I'd like to offer a different perspective.
DaveL's answer is helpful if you absolutely have to carry on being a "productive" person and attend critical events for your career or life in general, all those recommendations DaveL offered will reduce the amount of people you'll infect, but chances are you'll infect people anyway because many diseases are infectious since before you show symptoms and you don't need to sneeze to spread it, talking can spread some viruses too, (e.g. the seasonal influenza is contagious since before you even know you are infected⁽¹⁾).
[...] flu viruses are spread mainly by droplets made when people with flu cough, sneeze or talk.
[...] Most healthy adults may be able to infect other people beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Children may pass the virus for longer than 7 days. Symptoms start 1 to 4 days after the virus enters the body. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Some people can be infected with the flu virus but have no symptoms. During this time, those persons may still spread the virus to others.
The social aspect is why people are thanking you for even asking. So from a social perspective, DaveL's recommendations are also helpful if you want others to perceive you're trying not to get them infected, but in reality some people will know you should have stayed home because many people around you will get infected⁽¹⁾ (but most importantly, you should stay home to get better).
People with flu can spread it to others up to about 6 feet away.
First of all, you need the assistance of a professional to get properly diagnosed.
You need to know why you have this "common cold" symptoms, so your treatment is adequate for just having a common cold or something a bit more serious or a lot more dangerous, many illnesses display symptoms of the common cold (e.g. the flu, but the list is big).⁽²⁾
Several hundred different viruses may cause your cold symptoms.
In the mean time and while you get properly diagnosed, IMHO any disease that has the potential to be airborne infectious can be somewhat mitigated and contained following the procedures, precautions and advice given by CDC to contain and deal with the flu. So I will elaborate on that particular case (again, I can't stress this enough, ask for professional advice, this answer should only broaden your general sense of how to avoid contagion for you and for others to some degree).
Stay home if sick, or get vaccinated every season before you get sick (flu only).
- People will appreciate that you stood home better than sneezing or coughing "with the inner part of your arm" (which by the way is more ritual than safe practice, it is better to fully cover your mouth and nose⁽³⁾).
- If you are the type of person who can't afford to stay home if you catch the flu, then the more reason you should get vaccinated every season⁽⁴⁾ (Getting vaccinated won't protect you against anything and everything but it will protect you from a broad range of flu type viruses).
1. About Staying home.⁽⁵⁾
You don't "have to" attend anything that's not critical, attend your health and well being, that is critical. Staying home will dramatically reduce the amount of possible subjects to be infected, in this case your family, so stay home and follow all hygienic recommendations.
- Ventilate your house and specially your room, if you have a window to
the street, open that (unless it is raining outside).
- Change your sheets and blankets as regular as possible (every 2-3
days until 5 days after you recovered, 7 days for children). Do it
when you're alone and everyone else went to work/school. If you have
both washing and drying machines, great, if not, at least take them
out to the sun, do not keep infected used blankets inside your
If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness.
2. About Getting Vaccinated.⁽⁶⁾ (flu only)
The best prevention is not to get sick at all.
If you're not sick then you're not contagious.
The single best way to prevent the flu is to get a flu vaccine each season. The seasonal flu vaccine protects against the influenza viruses that research indicates will be most common during the upcoming season. There are several flu vaccine options for the 2014-2015 flu season.
Some additional info.
Virus that are so commonly transmitted like the flu are not going away anytime soon. Unless all potential hots/carriers get vaccinated at the same time repeatedly season after season until all types (A, B & C types)⁽⁷⁾ of influenza viruses die with no viable hosts to replicate and evolve on.
There are three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States. The emergence of a new and very different influenza virus to infect people can cause an influenza pandemic. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics.
Those viable hosts include more than 7 billion human beings and who knows how many animals that can carry along the virus and help it keep evolving⁽⁸⁾
And most importantly, consult your GP.
1. How Flu Spreads
2. Flu or Cold Symptoms?
3. Cover Your Cough
4. Preventing Seasonal Flu With Vaccination
5. Stopping the Spread of Germs at Home, Work & School
6. Key Facts About Seasonal Flu Vaccine
7. Types of Influenza Viruses
8. Transmission of Influenza Viruses from Animals to People